Of growing concern are threatened bioterrorist and warfare attacks using potentially lethal bacteria highly resistant to extreme environmental conditions. Some of the deadliest bacteria, for example anthrax (Bacillus anthracis), are also highly resistant to conventional sterilization agents and protocols. Contamination of public facilities with such bacteria constitutes a significant threat to human life with residual amounts of such bacteria being almost impossible to remove using current methods. Accordingly, building remediation has become a major priority among G8 nations (Dr. Steven Jones, Chair of the WHO Emerging and Dangerous Pathogens Committee, June, 2010).
Bacillus anthracis bacteria spores have a very long lifetime. At animal burial sites, they have been known to re-infect animals over 70 years after burial of an anthrax-killed animal.
There are many (c. 90) known strains of anthrax. The Vollum strain was developed but never used as a biological weapon during World War II, and is a particularly virulent strain. Another virulent strain is the Ames strain, which was used in 2001 anthrax bioterrorism attacks in the United States.
Anthrax can enter the human body by ingestion through the intestines, by inhalation through the lungs, or cutaneously through the skin. All three infection routes are of concern in the context of bioterrorism attacks with bacteria such as anthrax, but inhalation of an anthrax-contaminated environment in an enclosed room, and skin contact with anthrax contaminated objects, are of special concern since either or both can result from receipt of anthrax contaminated objects into an enclosed space such as an office. Respiratory infection with anthrax in humans initially manifests itself as cold or flu-like symptoms for several days, but then progresses quite suddenly to severe and commonly fatal respiratory collapse. If diagnosed early, anthrax infections can be treated with appropriate antibiotics, but not after the disease has progressed. Anti-anthrax vaccine is available for those known to be likely candidates for exposure, but this is not practical as a defense against anthrax-based bioterrorism.
Because of the dangers of experimenting with the highly toxic anthrax bacterium and its spores, it is common to experiment with another, less dangerous Bacillus species as a surrogate for anthrax, for example Bacillus subtilis. Results of deactivation treatment of B. subtilis are generally accepted as reliable indicators of effectiveness against Bacillus anthracis. 